The Philosopher's Index has long been the standard database of philosophy articles (though that might soon change, with PhilPapers mounting an impressive challenge). As one measure of the greater visibility of men than women in philosophy, I looked at the rates at which "she" and "he" appear in the Philosopher's Index article abstracts from 1940 to the present.
One interesting thing about analyzing abstracts is that mentioning someone in an abstract implies a high degree of attention to that person -- much higher than is implied by a passing reference (the usual target of bibliometric analysis). Moreover, if the abstract contains a pronoun, that implies that the person is being mentioned at least twice in the course of summarizing the article's content (first with proper name, then later with pronoun).
Here are the ratios in a graph:
In the 1940s, there were 293 abstracts containing the word "he" and 5 containing the word "she", a ratio of 59:1. So far in the present decade it's 5465 to 883, about 6:1 -- a large and fairly steady decline. However, even corrected to a logarithmic scale, it looks like the decline might be slowing (it's hard to be sure).
What does a 6:1 current ratio of "he" to "she" indicate? To explore this a bit more, I looked at usage patterns in 2013, randomly selecting 100 articles containing "he" and 100 articles containing "she".
Among the 100 "she" usages in 2013, 37 employed "she" with apparent generic, gender-neutral intent (e.g., "whenever an agent acts, she tries or wills to act"); 47 referred to a specific individual (usually a contemporary author whose view was being discussed); 8 used the phrase "he or she" or "he/she"; 6 were third-person references to the author herself; and 2 referred to a non-specific woman (e.g., to the mother in an article on surrogate pregnacy).
Among the 100 "he" usages, 7 employed "he" with apparent gender-neutral intent (e.g., "a doxastic state comprises the doxastic commitments an agent would recognise were he fully aware"); 86 referred to a specific individual (contemporary or historical); 2 used "he or she" or "he/she"; 2 were third-person references to the author himself; and 3 referred to God.
If we take these two 100-samples from 2013 as representative of the current decade, then we can multiply back by total occurrences in 2010-2014 to estimate a couple of interesting frequencies. 54.65 x 86 = an estimated 4700 occasions, so far this decade, in which a man's work is discussed centrally enough in the abstract for the author to employ the pronoun, compared to 8.83 x 47 = an estimated 415 occurrences for women -- about an 11:1 ratio of discussions of men to discussions of women. Thus, we can see that that the 6:1 ratio was actually somewhat misleadingly egalitarian if taken as a measure of discussion targets, due to fact that about half of the occurrences of "she" in the abstracts were using the generic "she" or "he or she".
(I also examined the 5 "she" abstracts and a random 100 "he" abstracts from the 1940s. "She" referred to an individual once, was used in a general "he or she" once, and was a third-person reference to the author 3 times. "He" was used with apparent gender-neutral intent 4 times, in a "he or she" once, to refer to a specific individual 17 times, and to refer to the author himself 78 times. In the 1940s, abstracts were much more likely to be written in the third person, and they were generally shorter, offering less occasion for a pronoun reference to an individual who is a target of discussion.)
We can also compare rates of generic "he" and "she" usage in the 2010s. It looks like "he" and "she" as (supposedly) gender-neutral pronouns are about equally common in current philosophical usage, while "he or she" and "he/she" were about half as common: "he" 54.65 x 7 = est. 383; vs. "she" 8.83 x 37 = est. 323; vs. "he or she"/"he/she" 54.65 x 2 + 8.83 x 8 = est. 180. (My sample contained no instances of "she or he" or "she/he".)
"They", of course, is more clearly gender neutral, though the formal propriety of its use in the singular remains unfortunately controversial, and I could find no clear instances of the singular "they" used in a sample of 100 "they"-containing abstracts from 2013 (e.g., no usages like "a doxastic state comprises the doxastic commitments an agent would recognise were they fully aware").